Paraffin wax compositions



3,102,040 Patented Aug. 27, 1963 3,102,040 PARAFFIN WAX COMPOSITIONS Malcohn S. Williams, El Cerrito, and Richard C. Fox, $211 Rafael, Calif.,' assignors to California Research Corporation, San Francisco, Calif.,. a corporation of Delaware No Drawing. FiiedMar. 31, 1960, Ser. No. 18,803

7 Claims. Il. 106-,270)

This invention pertains to improved wax compositions having high gloss characteristics.

This patent application is a continuation-ln-part' of patent application Serial No. 721,627, filed March 17,

1958, now abandoned.

Paraffin waxes have been used for many years for coating numerous surfaces. Because er .its eifectiveness in resisting water and water vapor transmission, paratfin wax has been used as a coating material for paper packages and wrappers, particularlyas coatings for milk cartons. Characteristics which are desirable in paraffin wax for such use include the high gloss, resistance to scuifing and flaking, low tackiness, and resistance to transmission of water and water vapor.

Although uncompounded paraffin waxes are used extensively, numerous additives have been included in wax compositions in attempts to obviate the inherent faults of waxes per se. For example, polyethylenes, polymethylenes, and polyisobutylenes have been added to paraffin waxto improve various propertiesthereof. Although polyisobutylenes increase the tensile strength of the wax,

the viscosity of the resulting wax composition is increased excessively, and the resulting polyisobutylene-wax composition blocks (that is, adjacent waxed surfaces under pressure stick together) at a lower temperature than the wax per se. Polyethylenes, on the other hand, may improve some properties of wax compositions, but the resulting polyethylene-paraifin wax compositions have higher water vapor transmission rates (i.e., permit greater transmission .of water through the wax coating).

A wax known as Fischer-Tropsch wax has long'been available for the preparation of wax compositions. It has been asserted that a Fischer-Tropsch wax can be used (I) as a wax,'or (2) as an additive for paraffin wax compositions. I

Fischer-Tropsch waxes can be used in coatings for paper when the wax-coated paper is water cooled subsequent to the coating step. That is, a paper sheet can be dipped in a melted Fischer-Tropsch wax, then shock cooled by immediately passing the hot coated waxed paper into a tank or trough of water. A'Fischer-Tropsch wax can be used in various amounts as an additive in paraffin wax compositions wherein the wax compositions are used to coat paper sheetings cooled subsequent to the coating step. 4

However, there are certain disadvantages found in the which are immediately waterdiscovered that calender cooled paraffin wax compositions having high gloss charatceristics are obtained by incorporating from 0.03% to 0.3%, by weight, of a Fischer- Tropsoh wax in certain particular pertroleum paraflin waxes. That is, the compositions of this invention comprise certain particular petroleum paratfin wax and from 0.03% to 0.3%, by weight, of a Fischer-Tropsch wax. v

In addition to having extremely high gloss character istics, the parafiin wax compositions of this invention have high tensile strength, low water vapor transmission rates,

good antiscuffing characteristics and low tackiness.

Furthermore, small concentrations of Fischer-Tropsch waxes in the particular wax compositions set forth herein result in the formation of wax compositions having high gloss characteristics (that is, calender cooled and air cooled waxed papers having high gloss characteristics) without the presence of undesirable striations of air cooled wax films.

The particular parafiin waxes (erg, petroleum paraffin waxes) which are improved by the addition thereto of the v Fischer-Tropsch waxes include paraflin waxes (and blends use of large amounts of Fischer-Tropsch waxes as addithen air cooled, the resulting waxed paper had a considerably lower gloss rating than a paper which had been coated with only parafiin Wax.

Therefore, it is a primary object of this invention to correct the deficiencies of calender cooled wax compositions set forthhereinabove for use in air or calender cooled wax fihns.

In accordance with the present invention, it has been American Melting Point, as

from 0.03% to 0.3%, tion; more preferably,

.addition of only 0.05%,

thereof) having average melting points in the range of F. to 155 F. AMP.

(The term AMP refers to defined in ASTM D-87-42.) Of the wax compositions available in the melting point range of 125 F. to 155 F., the preferred waxes are the petroleum refined paraffin waxes having melting points in the range of 139 F. to I142 F. AMP. Waxes having such melting points are obtained by blending petroleum refined paraffin waxes having melting points in the range of 125 F. to F. AMP with petroleum refined paraffin waxes having melting points in the range of 142 F. to. 153 F. AMP.

The phrase Fischer-Tropsch waxes means the waxes synthesized by the familiar Fischer-Tropsch processj By this process, coal is burned in the presence of oxygen and steam to produce hydrogen and carbon monoxide, which are then reacted in the presence of a catalyst to make the desired hydrocarbon Wax.

The particular Fischer-Tropsch waxes used herein were obtained under the trade name of Paraflint. This Fischer-Tropsch wax is a high molecular weight Wax having an average molecular weight in the range of about 750 to 1000; and it consists essentially of straight-chain hydrocarbons I The Fischer-Tropsch waxes are used herein in amounts by weight, of the finished composifrom 0.03% to 0.1%, by weight. As set forth in the data of Table I, hereinbelow, the by weight, of Fischer-Tropsch F. AMP improved the calender cooled gloss characteristics considerably over that of the para'ffin'wax per se. However, the addition of 1% of the same Fischer-Tropsch wax to the same paraffin wax reduced the gloss characteristic to a considerable degree below that of the par'afiin wax per se. That is to say, that the addition of an amount of 1% of the Fischer-Tropsch wax to the paraifin wax was detrimental to the final wax composition as to gloss characteristics. Table l hereinbelow presents [data on the effectiveness of the Fischer-Tropsch waxes as improving agents for the particular wax compositions described herein.

The wax A was a petroleum refined parafiin wax having a melting point range from 125 F. to 130 F. was a petroleum refined paraflin AMP. The wax B wax having a melting point range from 139 F. to 142 Gloss measurements were made with a 60 Gardner gloss meter using a standard setting of 100 for the reflectivity rating obtained for a polished, standard black plate. The water vapor transmission rate (WVTR) was measured by TAPPI Method T-448-M-49.

1 Air cooled waxed milk cartons.

2 Calender cooled waxed glassine paper.

The data presented in Table II hereinbelow further illustrates the effectiveness of small amounts of Fischer- Tropsch waxes in improving the gloss characteristics of waxes described herein.

Wax C was a blend consisting of 80%, by weight, of a California wax having a melting point of 142.5 F. AMP and 20% of a wax melting in the range of 128- 130 F. AMP.

Wax D was a blend consisting of 80%, by weight, of a California wax having a melting point of 142.5" F. AMP and 20% of a wax having a melting point of 127.7 F. AMP.

Table II Amount of Melting Fischer- Paraflin Wax Point, F., Tropsch (31055 1 AMP Wax,

Percent By Wt.

1 Calender cooled waxed glassine paper.

When papers (e.g., milk cartons) have been coated with the wax compositions of this invention, the wax coatings are cooled slowly (as opposed to shock cooling).

In the process of calender cooling papers coated with wax compositions, the paper to be waxed is passed through the molten w-ax compositions described herein (such as wax compositions consisting of 99.95% ofa parafiin wax characterized by a melting point of 139 F. to 142 F. AMP and 0.05% of a Fische-r-Tropsch wax), then onto a calender roll cooled with a cooling medium. The calender roll is usually not immediately. adjacent to the molten wax bath, so the paper with the molten wax thereon normally passes a distance in the air before reaching the calender roll.

With milk cartons, the milk carton is dipped in the molten wax, then withdrawn therefrom and suspended in the air at temperatures of 35 F. to 60 F. for a time suflicient to cool the wax composition.

We claim:

1. A paraffin wax compo, tion consisting essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch wax having an average molecular weight in the range l of about 750 to 1000, and the balance of said parafiin wax composition consisting essentially of a petroleum refined paraffin wax having an average melting point in the range of to 155 F. AMP.

2. A paraffin wax composition consisting essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch Wax having an average molecular Weight in the range of about 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined paraffin wax selected from the group consisting of a parafiin Wax having an average melting point in the range of 125 to F. AMP and a parafiin wax having an average melting point in the range of 139 to 142 F. AMP. 1

3. A paraflin wax composition consisting essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch wax having an average molecular weight in the range of I about 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined paraffin Wax having an average melting point in the range of 125 to 130 F. AMP.

4..A paraffin Wax composition consisting essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch wax having an average molecular weight in the range of about 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined parafiin 'Wax having an average melting point in the range of 139 to 142 F. AMP.

5. A paraffin wax composition consisting essentially .of 0.05% by weight of a Fischer-Tropsch wax having an average molecular weight in the range of about 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined parafiin wax having an average melting point in the range of 139 to 142 F. AMP.

6. A process of applying parafiin wax coatings onto paper comprising passing a paper strip through a molten wax composition then onto a cooled calender roll, wherein said wax composition consists essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch wax having an average molecular weight in the range of about 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined paratlin wax having an average melting point in the range of 125 to 130 F. AMP.

7. A process of applying paraffin wax coatings onto paper comprising passing a paper strip through a molten wax composition then onto a cooled calender roll, wherein said Wax composition consists essentially of from 0.03% to 0.1% by weight of a Fischer-Tropsch Wax having an average molecular weight in the range of 750 to 1000, and the balance of said wax composition consisting essentially of a petroleum refined parafiin wax having an average melting point in the range of 139 to 142 F. AMP.

References Cited in the file of this patent UNITED STATES PATENTS King Apr. 13, 1954 Jakaitis Jan. 10, 1961 OTHER REFERENCES 

1. A PARAFFIN WAX COMPOSITION CONSISTING ESSENTIALLY OF FROM 0.03% TO 0.1% BY WEIGHT OF A FISCHER-TROPSCH WAX HAVING AAN AVERAGE MOLECULAR WEIGHT IN THE RANGE OF ABOUT 750 TO 1000, AND THE BALANCE OF SAID PARAFFIN WAX COMPOSITION CONSISTING ESSENTIALLY OF A PETROLEUM REFINED PARAFFIN WAX HAVING AN AVERAGE MELTING POINT IN THE RANGE OF 125* TO 155*F. AMP. 